package com.yinquan.util;

import java.io.*;
import java.net.*;
import java.util.*;

import com.yishun.springboot.dao.CWRServiceTest;

import lombok.extern.slf4j.Slf4j;

/**
 * 将指定的HTTP网络资源在本地以文件形式存放
 * @date   2021年5月6日 下午7:20:35
 * @author XiaoHuang
 *
 */
@Slf4j
public class HttpGet {

  public final static boolean DEBUG = false;//调试用
  private static int BUFFER_SIZE = 8096;//缓冲区大小
  private Vector vDownLoad = new Vector();//URL列表
  private Vector vFileList = new Vector();//下载后的保存文件名列表

  /**
   * 构造方法
   */
  public HttpGet() {

  }

  /**
   * 清除下载列表
   */
  public void resetList() {
    vDownLoad.clear();
    vFileList.clear();
  }

  /**
   * 增加下载列表项
   */
  public void addItem(String url, String filename) {
    vDownLoad.add(url);
    vFileList.add(filename);
  }

  /**
   * 根据列表下载资源
   */
  public void downLoadByList() {
    String url = null;
    String filename = null;
    
    //按列表顺序保存资源
    for (int i = 0; i < vDownLoad.size(); i++) {
      url = (String) vDownLoad.get(i);
      filename = (String) vFileList.get(i);

      try {
        saveToFile(url, filename);
      }
      catch (IOException err) {
        if (DEBUG) {
          log.info("资源[" + url + "]下载失败!!!");
        }
      }
    }

    if (DEBUG) {
      log.info("下载完成!!!");

    }
  }

  /**
   * 将HTTP资源另存为文件
   */
  public void saveToFile(String destUrl, String fileName) throws IOException {
    FileOutputStream fos = null;
    BufferedInputStream bis = null;
    HttpURLConnection httpUrl = null;
    URL url = null;
    byte[] buf = new byte[BUFFER_SIZE];
    int size = 0;
    
    //建立链接
    url = new URL(destUrl);
    httpUrl = (HttpURLConnection) url.openConnection();
    //连接指定的资源
    httpUrl.connect();
    //获取网络输入流
    bis = new BufferedInputStream(httpUrl.getInputStream());
    //建立文件
    fos = new FileOutputStream(fileName);

    if (this.DEBUG) 
  log.info("正在获取链接[" + destUrl + "]的内容...\n将其保存为文件[" + fileName + "]");

    //保存文件
    while ( (size = bis.read(buf)) != -1) 
      fos.write(buf, 0, size);
    
    fos.close();
    bis.close();
    httpUrl.disconnect();
  }

  /**
   * 主方法(用于测试)
   */
  public static void main(String argv[]) {

    HttpGet oInstance = new HttpGet();
try {
//增加下载列表（此处用户可以写入自己代码来增加下载列表）
               oInstance.addItem("http://gimg.baidu.com/img/net.gif","C:\\tempStoreYzwImg\\testimg.gif");
        //开始下载
oInstance.downLoadByList();
    }
    catch (Exception err) {
      log.info(err.getMessage());
    }

  }

}

